Ambiguity-free Doppler centroid estimation technique for airborne SAR using the Radon transform

Kong, Young-Kyun; Cho, Byung-Lae; Kim, Youngsoo

doi:10.1109/tgrs.2005.843955

Cited by 92 publications

(7 citation statements)

References 8 publications

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“…In terms of parameter estimation, the research focuses on the estimation of Doppler centroid frequency and Doppler frequency modulation rate. The estimation methods of the former mainly include the energy equalization method, clutter locking method, radon transform method radon-transform-based method and its improved form [26][27][28][29]. The latter is represented by the map-drift method [30].…”

Section: Motion Error Compensationmentioning

confidence: 99%

A Modified Range Doppler Algorithm for High-Squint SAR Data Imaging

Guo,

Wang,

Men

et al. 2023

Remote Sensing

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The high-squint airborne Synthetic Aperture Radar (SAR) has the ability to detect the target area flexibly, and the detection swath is significantly increased compared with the side-looking SAR system. Therefore, it is of great significance to carry out research on high-precision imaging methods for high-squint airborne SAR. However, the high-squint SAR echoes have large Range Cell Migration (RCM), resulting in severe range–azimuth coupling and strong spatial variation. In this paper, a Modified Range Doppler Algorithm (MRDA) is proposed to cope with these effects introduced by the significant RCM in high-squint airborne SAR imaging. The bulk compensation preprocessing is first adopted to remove the considerable RCM and severe cross-coupling in a two-dimensional frequency domain. Then, Non-Linear Chirp Scaling (NLCS) in the range direction is utilized to equalize the range-variant chirp rate caused by the residual RCM and coupling and, therefore, the consistent range phase compensation can be fulfilled in range frequency domain. The modified correlation processing is executed to compensate the residual Doppler phase modulation, the residual RCM and the range-variant cubic phase modulation, which guarantees the characteristics of high efficiency and high precision. The simulations have demonstrated that the MRDA can focus the SAR echoes with large squint angles more effectively than the algorithms based on the Linear Range Walk Correction (LRWC) method.

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Section: Motion Error Compensationmentioning

confidence: 99%

A Modified Range Doppler Algorithm for High-Squint SAR Data Imaging

Guo,

Wang,

Men

et al. 2023

Remote Sensing

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“…The application of specific algorithms (e.g. clutterlock) could be necessary to track Doppler centroid over the used SAR image (Kong et al 2005). It can also been seen from the Equations (1) and (2) that the uncertainty of Doppler centroid frequency can have a direct effect on the accuracy of ground SAR object positioning.…”

Section: Radargrammetric Geometrymentioning

confidence: 99%

Two-sided long baseline radargrammetry from ascending-descending orbits with application to mapping post-seismic topography in the west Sichuan foreland basin

et al. 2014

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One-sided ascending or descending Synthetic Aperture Radar (SAR) stereoradargrammetry has limited accuracy of topographic mapping due to the short spatial baseline (~100 km) and small intersection angle. In order to improve the performance and reliability of generating digital elevation model (DEM) from spaceborne SAR radargrammetry, an exploration of two-sided stereoradargrammetry from the combination of ascending and descending orbits with geometric configuration of long spatial baseline (~1000 km) was conducted in this study. The slant-range geometry between SAR sensors to the earth surface and the Doppler positioning equations were employed to establish the stereoscopic intersection model. The measurement uncertainty of two-sided radargrammetric elevation was estimated on the basis of radar parallax of homogeneous points between input SAR images. Two stereo-pairs of ALOS/PALSAR (Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar) acquisitions with the orbital separation almost 1080 km over the west Sichuan foreland basin with rolling topography in southwestern China were employed in the study to obtain the up-to-date terrain data after the 2008 Wenchuan earthquake that hit this area. The quantitative accuracy assessment of two-sided radargrammetric DEM was performed with reference to field GPS observations. The experimental results show that the elevation accuracy reaches 5.5 m without ground control points (GCPs) used, and the accuracy is further improved to 1.5 m with only one GPS GCP used as the least constraint. The theoretical analysis and testing results demonstrate that the twosided long baseline SAR radargrammetry from the ascending and descending orbits can be a very promising technical alternative for large-area and high accuracy topographic mapping.Citation: Chen HQ, Chen Q, Liu GX, et al. (2014) Two-sided long baseline radargrammetry from ascending-descending orbits with application to mapping post-seismic topography in the west Sichuan foreland basin. Journal of Mountain Science 11(5).

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“…One is the incoherent integration, and the other is the coherent integration. The typical incoherent integration techniques include the Radon transform 4 and Hough transform 5 . They integrate the signal energy along the trajectories with different angles, and choose the angle with the maximum integration value as the target track.…”

Section: Introductionmentioning

confidence: 99%

Radar high-speed maneuvering weak target detection based on radon dynamic path optimization and fixed point iteration

Hou

2024

J. Appl. Rem. Sens.

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Long-time coherent integration is known as a powerful method to detect the weak target. However, its effectiveness is limited by the target motion across range and Doppler bins. For the high-speed target, it is highly possible that the range bin crossing (RBC) problem occurs, and for maneuvering target, the Doppler bin crossing (DBC) problem cannot be neglected. In this paper, we propose a Radon dynamic path optimization and fixed point iteration method to deal with the RBC and DBC problem, and thus make the radar able to detect the high-speed maneuvering weak target effectively. Radon transform is essentially a parameter searching method to find the target range moving path. We derive a cost function based on the property of the slow time time-frequency and frequency-time matrix, and solve it with the dynamic path optimization and fixed point iteration algorithm. The proposed method does not demand any a priori information,and is free of the ambiguity of the velocity or the acceleration caused by the potential undersampling of the slow time. Both the simulated and real Radar echo signals validate the effectiveness of the proposed method.

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Ambiguity-free Doppler centroid estimation technique for airborne SAR using the Radon transform

Cited by 92 publications

References 8 publications

A Modified Range Doppler Algorithm for High-Squint SAR Data Imaging

A Modified Range Doppler Algorithm for High-Squint SAR Data Imaging

Two-sided long baseline radargrammetry from ascending-descending orbits with application to mapping post-seismic topography in the west Sichuan foreland basin

Radar high-speed maneuvering weak target detection based on radon dynamic path optimization and fixed point iteration

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